public class MySingleList{
    static class ListNode{
        public int val;//列表值域
        public ListNode next;//下一个节点地址

        public ListNode(int val){
            this.val = val;
        }
    }

    public ListNode head;//表示当前列表的头节点

    public void createList() {

        ListNode node1 = new ListNode(12);
        ListNode node2 = new ListNode(23);
        ListNode node3 = new ListNode(34);
        ListNode node4 = new ListNode(45);
        ListNode node5 = new ListNode(56);

        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;

        this.head = node1;

    }

    //头插法
    public void addFirst(int data){
        ListNode node = new ListNode(data);
        node.next = head;
        head = node;

    }
    //尾插法
    public void addLast(int data){
        ListNode node = new ListNode(data);
        ListNode cur = head;
        if (cur == null){
            head =node;
            return;
        }
        while (cur.next != null){
            cur = cur.next;

        }
        cur.next = node;
    }
    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index,int data){
        if (index < 0 || index > size()){
            System.out.println("信息不合法");
            return;
        }
        if (index == 0){
            addFirst(data);
            return;
        }
        if (index == size()){
            addLast(data);
            return;
        }
        ListNode node = new ListNode(data);
        ListNode cur = head;
        int count = 0;
        while (count != index -1){
            cur = cur.next;
            count++;
        }
        node.next = cur.next;
        cur.next = node;

    }
    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key){
        ListNode cur =head;
        while (cur != null){
            if (cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key){
        if (head.val == key){
            head = head.next;
            return;
        }
        ListNode cur = head;
        while (cur.next != null){

            if (cur.next.val == key){
                cur.next = cur.next.next;
                return;
            }
            cur = cur.next;
        }
    }

    //删除所有值为key的节点
//    public void removeAllKey(int key){
//        if (head.val == key){
//            head = head.next;
//        }
//        ListNode cur = head;
//        while (cur.next != null){
//
//            if (cur.next.val == key){
//                cur.next = cur.next.next;
//            }
//            cur = cur.next;
//        }
//    }
    public void removeAllKey(int key) {
        // 处理头节点值等于 key 的情况，使用循环确保所有连续的头节点值等于 key 的节点都被删除
        while (head != null && head.val == key) {
            head = head.next;
        }
        // 如果头节点为空，说明链表为空，直接返回
        if (head == null) {
            return;
        }
        // 从头节点的下一个节点开始遍历
        ListNode cur = head;
        while (cur.next != null) {
            if (cur.next.val == key) {
                // 如果 cur 的下一个节点值等于 key，跳过该节点
                cur.next = cur.next.next;
            } else {
                // 如果 cur 的下一个节点值不等于 key，移动 cur 指针
                cur = cur.next;
            }
        }
    }
    //得到单链表的长度
    public int size(){
        int count = 0;
        ListNode cur = head;
        while ( cur != null){
            cur = cur.next;
            count++;
        }
        return count;
    }
    public void clear() {
        this.head = null;
    }
    public void display() {
        ListNode cur = head;
        while (cur != null){
            System.out.println(cur.val);
            cur = cur.next;
        }
        System.out.println();
    }



}

